Prcduction of azo dyes



dye, and the latter canjbe separated by the" steam hot or cold) and UNITED 'sT TEs Parana 0mm I JOHN LAVERY 0F PHILADELEHIA, PENNSYLVANIA.

PRODUCTION OF AZO DYES.

No Drawing.

To all whom it may concern:

Be it known that I, JOHN L. KANE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in the Production of A20 Dyes, of which the following is a specification.

The present invention relates to the production of azo dyes by an improved method whereby the dyes acquire substantially greater brilliancy, strength; and depth of; color, and pureness of tone than are secured in the production of dyesin the ordinary methods heretofore described. This result is secured, according to the present invention,'by the employment of starch or starchy materials, in the treatment of intermediates, especially those intermediates which consist of aromatic amino bodies, including anilin as typical bodies of this group.

- The following specific example is given, it

being understood that this-is given as an" illustration merely of the invention, and not as limiting the invention thereto:

Starch paste is first prepared by adding, say, 2530% of dry starch to water, and then heatin for example on a' water bath or hath, to 70-80 C.

To 4: parts of this starch paste, is added 9.3 parts of anilin, and 100 parts of water 36 parts of strong 1101 1.2 S. G.), and the mass well stirred. The mixture is then cooled to below 5 (1, for example by adding ice. More HCl can be added if desired, and 7.2 parts of sodium nitrate dissolved in a small amount of water, is slowly added, while stirring and while maintaining the temperature at not above 5 (1., for diazotization. This mixtureis then poured slowly, into a solution in, say, 400 parts of cold water, of 11 parts of meta phenylene diamin. The stirrin is continued until the completion of which requires only a short time.

The resulting product is'a solution of the usual methods, such asby salting out.

It is understood that in place of anilin,

' various other amino aromatic bodies can be used.zJLikewise, in place of meta phenylene diamin, eluding diamino and the like. It is also understood that if an alkaline solution is to be employed for the in water, which has the re .jreaction,

tizing the amino body andcoupllng with an various other aromatic bodies, inbodles, monoamino bodies.

Specification of Letters Patent. I Patented Rial. 16, 1920. Application filed June 19, 1919. Serial No. 305,253.

coupling, phenolic bodies, sulfonic acid compounds of phenolic bodies and the like can be used.

The dye produced in the above specific example is a yellowish-brown powder soluble properties of dyeing wool, silk and tannin-mordanted cotton, a brilliant orange color, somewhat darker in shade than the dye which would be produced if the anilin were diazotized and coupled Wlth meta phenylene diamin without the treatment with starch. The dyes produced; in accordance with the present invention are also fperfectly fast to light and washing.

A ter the complete mixing of the anilin with the starch paste and hydrochloric acid,

produced the separation of what ap the material being there is pears to be free carbon,

black and insoluble.

Starches from varioussources can be used,

including potato starch, wheat starch, maize starch, rye starch, sago, and the starches obtained from various table products. It is to be understood that the amount of starch can be varied, depending upon the particular intermediates used, and other conditions.

While the dye produced by diazotization of anilin and the coupling with meta phenyl- .ene diamin (without the starch treatment) gives better results when. a small amount of acetic acid (say 0.2% relative'to the volume of the dye bath), the dyefproducedin the above specific example gives better results without the addition of this acid, thereby efi'ecting a saving. i

I claim: V 1. In the production ofazo dyes, the imother plants or vege- 1 provement which comprises treating an amino aromatic body with a starchy material, while-in an aqueous vehicle.

2. A process which comprises heating starch in water, adding a mineral acid, and an amino. aromatic body, thereafter diazoaromatic derivative to forma dye. 3. A process which comprises heating starch in water, adding-a--m1neral acid, an

comprises treating etc, then and coupling with an aromatic '5. lhe rocess which comprises treating which new dyes can be obtained by adding anilin with an acid and starch paste, then starch paste to the aromatic amins before diazotizing and coupling with meta phenyldiazotization, and thereafter coupling in the 10 ene diamin. known manner.

5 6. A class of azo dyes of enhanced bril- In testimony whereofI affix my signature.

liancy, clearness and strength of color; as

compared with the hitherto known azo dyes, JOHN LAVERY KANE. 

